1. Technology Field
The present disclosure relates to a fleet maintenance method and an in-vehicle communication system.
2. Description of Related Art
Along with the development of technologies and vehicles, people travel around more often than before, and accordingly, an information system that can provide destination guidance or map navigation is deeply desired. Thanks to the widespread of personal mobile devices and the commercialization of the Global Position System (GPS), GPS navigation devices have been brought into the market.
An existing portable electronic device can be integrated with GPS techniques and used for navigation and positioning, especially for the navigation and positioning of various vehicles, ships, and airplanes. The portable electronic device may be a portable electronic device with a built-in or add-on GPS antenna module, such as a mobile phone, a personal digital assistant (PDA), or a navigator. Nowadays, people like to bring electronic devices with GPS function when they travel around. Navigation software and other map data of different zones are usually stored in such an electronic device so that a user can drive his vehicle in an unacquainted zone according to the electronic map of the zone displayed in the screen of a navigator.
However, the aforementioned GPS navigation device can only provide the position of the vehicle but not allow the vehicle to communicate with a current fleet. In order to allow vehicles to communicate with each other, the Federal Communications Commission (FCC) provides a bandwidth of 5.85-5.925 GHz for the communication between vehicles and between vehicle and roadside units (RSUs). To be specific, each vehicle is equipped with some storage devices and transceiver units so that the vehicle can be considered a mobile router that can store or transmit messages. This technique is especially applied to telematic entertainment services and traffic safety.
A vehicle ad-hoc network (VANET) formed between communication devices in different vehicles is considered a special application of the mobile ad-hoc network (MANET). In a VANET, vehicles are considered mobile nodes distributed on the roads, and these vehicles move around in a special way to form a network topology and network features different from those of a general MANET. For example, when a fleet including a plurality of vehicles goes on the road, the network of the fleet may be broken or terminated by different road conditions (for example, traffic lamps and traffic jam, etc). More importantly, the quality of services (QoS) may be reduced due to the lack of a reliable transmission medium between the vehicles.
FIG. 1 is a diagram of a travelling fleet. Referring to FIG. 1, the fleet includes vehicles 102, 104, 106, 108, 110, 112, 114, and 116. When the fleet travels, the vehicles 102, 104, 106, 108, 110, 112, 114, and 116 may be scattered and accordingly cannot know the positions of each other due to some road conditions (for example, traffic lamp and traffic jam, etc).
Thereby, when people travel in a fleet, it is very important to keep every vehicle in the fleet or allow a leader of the fleet to know the current position of each vehicle in the fleet.